#define _CRT_SECURE_NO_WARNINGS 1
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
const int N = 1010;
int m, n, len = 1;
int a[N] = { 1 }, b[N] = { 1 }, c[N] = { 1 };

void add() {
	int jw = 0;
	for (int i = 0; i < len; i++) {
		c[i] = a[i] + b[i] + jw;
		jw = c[i] / 10;
		c[i] = c[i] % 10;
	}
	if (jw != 0) {
		c[len] = jw;
		len++;
	}
	for (int i = 0; i < len; i++) {
		a[i] = b[i];
		b[i] = c[i];
	}
}

int main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> m >> n;
	for (int i = 3; i <= n - m + 1; i++) add();
	for (int i = len - 1; i >= 0; i--) cout << c[i];
	return 0;
}